Generation of Methyl Vinyl Ketone from Oxidation of Levulinic Acid Oxidized by Cupric Oxide Complex

Ministry of Science and Technology of China [2010CB732201]; National Natural Science Foundation of China [U0733001, 50776035]Methyl vinyl ketone (MVK) is a kind of high-value chemical which has been widely used in many fields. In this paper, it is formed from oxidation of levulinic acida hydrolysis product of biomass. Copper oxide supported on cerium dioxide (CuO/CeO2) and alumina (CuO/Al2O3) were prepared and used for the oxidation of levulinic acid (LA). The oxidants were characterized by means of X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR) and atomic force microscope (AFM) techniques. CuO/CeO2 and CuO/Al2O3 show a different behavior with respect to pure CuO. The experiments revealed that CuO/CeO2 and CuO/Al2O3 can oxidize LA and get methyl vinyl ketone [yield of 15.5% detected by head space-gas chromatograph-mass spectrometer (HS-GC-MS)] under mild reactive conditions, while pure CuO oxidizes LA to produce butanone (MEK)

Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3), exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed

Process optimization for the production of high-concentration ethanol with Scenedesmus raciborskii biomass

Scenedesmus raciborskii WZKMT was subjected to fed-batch enzymatic hydrolysis and fermentation to facilitate the saccharification of high-solid-loading substrate for high-concentration ethanol. In this work, process factors affecting enzymatic hydrolysis, including enzyme loading, temperature, pH, and solid loading, were optimized. Results showed that 58.03 g L-1 glucose, 12.57 g L-1 xylose, and 1.45 g L-1 cellobiose were obtained after the enzymatic hydrolysis of 330 g L-1 substrates under the optimal conditions of 30 FPU g(-1) enzyme loading, 50 degrees C, and pH 5.5. Meanwhile, 89.60% yield and 30.43 g L-1 content of ethanol were obtained after the fermentation of 330 g L-1 hydrolysate. The maximum ethanol concentration of 79.38 g L-1 could be achieved through repeated fed-batch process, indicating that S. raciborskii WZKMT is a promising feedstock for ethanol production

Hydrogenation of Ethyl Acetate to Ethanol over Ni-Based Catalysts Obtained from Ni/Al Hydrotalcite-Like Compounds

A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physico-chemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The results indicated that Ni/Al HTlcs with layered structures could be successfully prepared by the coprecipitation method, and the characteristic HTlcs reflections were also observed in the XRD analysis. The NiO and Ni0 phases were identified in all Ni-based catalysts, which displayed randomly interconnected pores and no layer structures. In addition, the studies also found the Ni/Al HTlcs and Ni-based catalysts had high specific surface areas, low pore volumes and low pore diameters. The catalytic hydrogenation of ethyl acetate to ethanol with Ni-based catalysts was also investigated. Among the studied catalysts, RE1NASH-110-3 showed the highest selectivity and yield of ethyl acetate to ethanol, which were 68.2% and 61.7%, respectively. At the same time, a major by-product, butyl acetate, was formed due to an ester-exchange reaction. A proposed hydrogenation pathway for ethyl acetate over Ni-based catalysts was suggested